The need for tightly bonded, resilient, permanent denture liners clearly exists. Because currently available liner materials are unsatisfactory, a study of four alternative materials is proposed. The candidate elastomers are: phosphonitrilic fluoroelastomers, chlorinated polyethylenes, polyurethanes, and triblock domain polymers. Each of these is commercially or semicommercially available, relatively low priced, biocompatible, and, judging from their physical parameters, suitable for the intended applications. Preliminary studies have shown that the phosphonitrilic fluoroelastomers and the domain polymers are good candidate materials. It was shown that they could be firmly bonded to the hard denture base and remained bonded after 30 days immersion in water. The commonly used flasking technique was slightly changed to fabricate these lined dentures. Previous experience by the authors with the other two elastomers in similar applications indicate that these are also well suited for the denture liner application. The proposed investigation is a five-year effort comprising chemical/physical testing and preclinical and clinical evaluations. It is expected that materials and techniques will be developed which can be used by dental technicians using "normal" equipment. It is also intended to develop an in vitro testing procedure which will predict the wearability of new denture liner materials in general based strictly on data derived from physical testing. This outline of the proposed studies is based on a previous grant application and on the subsequent suggestions by its reviewers. It is a cooperative effort of Gulf South Research Institute, the Louisiana State University School of Dentistry, and Tulane University, all in New Orleans, Louisiana.